add preview

build/index.js

@@ -0,0 +1,31 @@
+const { run } = require('runjs')
+const chalk = require('chalk')
+const config = require('../vue.config.js')
+const rawArgv = process.argv.slice(2)
+const args = rawArgv.join(' ')
+
+if (process.env.npm_config_preview || rawArgv.includes('--preview')) {
+  run(`vue-cli-service build ${args}`)
+
+  const port = 9526
+  const basePath = config.baseUrl
+
+  var connect = require('connect')
+  var serveStatic = require('serve-static')
+  const app = connect()
+
+  app.use(
+    basePath,
+    serveStatic('./dist', {
+      index: ['index.html', '/']
+    })
+  )
+
+  app.listen(port, function() {
+    console.log(
+      chalk.green(`> Listening at  http://localhost:${port}${basePath}`)
+    )
+  })
+} else {
+  run(`vue-cli-service build ${args}`)
+}